基于土壤养分和重金属毒害效应的宁都县优质烟草土壤适宜性评价

Soil Suitability Evaluation of High Quality Tobacco Based on Soil Nutrient and Toxic Effects of Heavy Metals in Ningdu

为了评价宁都县植烟区优质烟草土壤的适宜性,为土壤的施肥和管理提供参考依据,以土壤养分和重金属毒害效应指标为评价因子,进行了优质烟草土壤适应性评价和影响因素分析。采用模糊数学模型隶属度法对1522组土壤样品进行了分析和综合评价,pH值、OM、TN、TP、TK、AN、AP、QK隶属度的计算采用抛物线型函数;结合烟草种植和土壤质量限值要求,Cr、Cd、Pb、Hg隶属度的计算采用降半梯形函数。结果显示:pH值、TK、TP的隶属度均值均低于0.20,QK、AP、Pb、OM的隶属度均值介于0.40~0.50,AN、TN和重金属的隶属度均值均大于0.80,属于优良等级,地质背景和典型种植制度、土地利用类型是指标隶属度的主要影响因素;SFI范围为0.27~0.93,均值为0.57,变异系数为0.16,块金效应值为0.66,土壤适宜性中等等级面积占比为85.1%,一般等级面积占比为14.4%,土壤AP、QK、AN是SFI的关键影响因素,种植制度是SFI的首要影响因素,其次是地质背景。研究区土壤总体适宜性为一般等级。QK、AP含量达到一般等级,人为因素影响显著,空间相关性差,建议加强科学施肥或间作,保持或提高钾肥、磷肥的使用;AN含量达到优良等级,人为因素影响较弱,空间相关性较强,表明土壤氮供给能力较强,建议控制氮肥的使用。

In order to analyze and evaluate the level of soil suitability for high quality tobacco in Ningdu tobacco-planted area and provide reference for soil fertilization and management,1522 topsoil were collected,Soil Feasibility Index(SFI)basing on soil nutrient and toxic effect of Heavy metals were evaluated by fuzzy mathematical theory,and the influencing factors of SFI were discussed.Combined limits of quality tobacco-planted and soil quality,degree of membership(DM)function of pH,organic matter(OM),total N(TN),total P(TP),total K(TK),available N(AN),available P(AP),and available K(QK)were parabolic line shape,and DM function of Cr,Cd,Pb and Hg were falling half trapezoid function.The results indicated that the average DM of pH,TK,TP was less than 0.2.For OM and TK,the high contents leaded to the decrease of DM.The average DM of QK,AP,Pb and OM was form 0.4 to 0.5.The average DM of AN and TN exceed 0.8.The main influencing factors of DM were geological background,cropping system and land use type.The range of SFI was from 0.27 to 0.93.The average,CV and nugget effect value of SFI were 0.57,0.16 and 0.66.The proportion of area for normal and good were 85.1%and 14.4%,and AP,QK and AN were the key influencing factors.The cropping system was the main influencing factor.For QK and AP,human factor had an obvious influence,and the spatial correlation was weak.It was suggested to strengthen scientific fertilization or plant rotation,maintain or improve the use of available potassium,phosphorus fertilizer.When AN content was the excellent grade,the impact of human factors was weak,and spatial correlation was strong,which indicated that soil nitrogen supply capacity was strong.It was suggested to control the use of nitrogen fertilizer.